There is a growing number of drugs and vaccines for which the most effective, or most convenient method of administration is by delivery of a spray or mist. A variety of devices are known for delivering a controlled amount of a pharmaceutical preparation in a spray, stream or mist to the nose, eye, ear, lungs, oral mucosal membranes, such as in the buccal region, or throat of a user, or for topical delivery of an active agent. Various devices for systemic or topical delivery of a liquid or even a powdered formulation include a measured amount of a pharmaceutical composition contained in a crushable ampoule, blister or other dosage form that is forced against a penetrating device during use, to pierce the dosage form and release the contents.
The effectiveness of this type of dosage depends on the ability to deliver a precisely measured amount of active agent through a small opening with enough force and with control of the spray, stream or mist geometry to ensure that the correct amount of active agent reaches the desired target. This is of particular importance as more drugs and vaccines are being delivered to the eye, oral mucosal membranes, nasal mucosa or to the lungs through the nasal passages. It is a further advantage if the active agents can be stored and delivered from the same dosage form without the risk of contamination prior to delivery.